On Saturday, the 27th anniversary of the Bhopal disaster in India that killed 20,000 people will be commemorated by World No Pesticides Use Day. This year, it is also the start of a three-day public trial of pesticide companies by the Permanent People's Tribunal (PPT), an international opinion tribunal that has raised awareness of cases from Eritrea to Guatemala.

It will convene in Bangalore, India, to hear cases brought against the big six pesticide companies; Monsanto, Dow, BASF, Bayer, Syngenta and DuPont, which control 74% of the global pesticide market. The PTT will invite the companies to defend an allegation of violating human rights. The World Bank estimates that more than 350,000 people each year die of unintentional pesticide poisoning - close to 1,000 people a day. Pesticide Action Network (PAN) International, which is spearheading the PPT, says that up to 41 million people suffer from adverse effects of pesticide exposure.

But it's not just people that have been killed and maimed by these toxic chemicals. Since a new class of systemic pesticide, called neonicotinoids - which move through the plant to the the flowers, attacking insects' nervous system on contact - appeared on the market two decades ago they have been linked to the worrying worldwide deaths of honeybees.

In Germany, Italy, France, and Slovenia, a Bayer-manufactured neonicotinoid, imidacloprid has been suspended as a seed dressing for corn following research showing it contaminated the pollen the bees collect and feed to their young and could, in laboratory conditions, impair honeybees' communication, memory and learning abilities. Beekeepers in Italy and France also blame another neonicotinoid, thiamethoxam, produced by Syngenta, for killing their bees and studies have shown how bees' flight could be adversely affected by the absorption of very low doses.

In the US, where a third of honeybees were wiped out in 2008, scientists have found imidacloprid at higher levels than had ever been reported before in the field. Although the mysterious disappearance of bees, dubbed colony collapse disorder, is likely caused buy a combination of factors, even the head of the US Department of Agriculture's Bee Research Laboratory believes that exposure to pesticides is a critical factor, along with parasites and poor nutrition.

PAN UK is inviting witnesses to give evidence at the PPT, but until the hearing begins PAN says it can't give out the their names. The defendants will be summoned to offer responses. Whether they turn up is unknown. You can watch the hearings live here.

The PPT, which cannot impose legal penalties, was set up in 1979 to raise awareness of human rights violations because there is no international forum empowered to hear and make judgment on cases of human rights violations brought against global corporations. In 1996, after the session of PPT on industrial hazards and human rights in Bhopal, the Charter on Industrial Hazards and Human Rights was adopted.

My opinion, and that of others, is that there is an overwhelming body of evidence pointing the finger at the sub-lethal impact of pesticides on bees, isn't it time that their creators were held to account?